The invention relates to a motor vehicle bumper with a interior bumper unit which can be fastened to a vehicle body and an exterior bumper unit fastened section-wise to the interior bumper unit.
German Patent 27 02 691 C3 has disclosed a motor vehicle bumper with an interior motor vehicle bumper unit and an exterior bumper unit. To affix the exterior bumper unit the latter is pushed over the interior unit and fastened to it with snap fasteners. The exterior bumper unit consists of plastic. For the support of the exterior bumper unit the latter is supported on its full surface by the interior part below its upper as well as its lower edge. The interior bumper unit is configured as a rigid support which is fastened to a vehicle with mountings of energy-absorbing construction.
A motor vehicle bumper disclosed in European Patent 0 430 665 B1 (FIG. 8) has an exterior unit and an interior unit supporting the exterior unit. In normal operation, a heavy stress on the bumper is to be expected only in the area of the rear sill portion. Since only this heavily stressed part is supported, a saving of material and weight can be achieved in comparison with conventional bumpers whose interior units support an exterior unit over the entire width of the upper and lower side.
A saving of weight and material is to be achieved by the invention in a motor vehicle bumper.
For this purpose, according to the invention, a motor vehicle bumper is provided with an interior bumper unit which can be fastened to a vehicle body, and an exterior bumper unit which can be fastened section-wise to the interior bumper unit, wherein the interior bumper unit support the exterior bumper unit only at rear sill portion of the exterior bumper unit, which is to be situated beneath a motor vehicle""s trunk lid.
In normal operation of the vehicle great stress upon the bumper is to be expected only in the area of the rear sill. Since only this latter, highly stressed area is supported, a saving of material and weight in comparison with conventional bumpers whose interior portions support an external portion over the entire width of the upper or lower side.
In further embodiment of the invention, the interior bumper unit has a ribbed structure.
By these measures a very great stiffness can be achieved, accompanied by a saving in weight.
It is likewise advantageous to provided the interior bumper unit with cutouts.
In this manner, material and weight can be saved without impairing the stiffness of the interior part.
In further embodiment of the invention, the interior bumper unit runs from the first fastening means for fastening the vehicle body toward the rear sill portion, substantially along the vehicle body, and has underneath the sill portion at least one balcony-like projection reaching in the direction of the length of the vehicle.
By these measures space can be created for a plastic deformation of the exterior bumper unit as well as for any energy-absorbing components. Furthermore, in the space available below the balcony, components such as sensors, antennas or the like can be disposed. Nevertheless, the area of the rear sill portion is supported. An additional saving of material and weight can be achieved by balconies disposed side by side in the transverse direction of the vehicle.
In further embodiment of the invention the interior bumper unit has a clip strip running transversely across the vehicle, into which an edge of the exterior bumper unit facing the vehicle body is clipped. Advantageously, the clip strip is provided with retaining ribs running in the lengthwise direction of the vehicle and substantially perpendicular to the transverse direction of the vehicle.
By these measures an edge of the exterior bumper unit, provided if desired with catch means, can be held. By means of the clip ribs a secure fastening as well as a saving of material as compared with a full-surface clip strip. For the adjustment of the fastening, clip ribs are easier to adapt than a full-surface ramp or strip. This is especially advantageous if the clip strip is made of injection-molded plastic and an injection mold is to be adapted to it.
The problem on which the invention is based is also solved by a motor vehicle with a bumper according to the invention in which a deformation body is fastened to the vehicle body underneath the interior bumper unit and is covered by the exterior bumper unit.
This division into deformation body and interior unit makes it possible to select the materials of the interior unit and deformation body according to their function. For example, the interior unit can consist of injection-molded plastic while the deformation body is made of aluminum.